Cork, (Gk. phellos), is a compressible wood having low water absorption derived from the meristem bark of live oaks. It has been known to be in use since 400 BC. Cork has been used to close bottles, and in particular wine bottles, since the 1600's. The elastically compressible nature of cork, coupled with its low absorption of water, make it ideally suited as a closure material, because it conforms to openings, even those having a somewhat irregular shape, forming a water tight seal.
Cork is still in use today by wine vintners, in part because of its historically proven successful performance, and also because it embodies the public's perception of the bottling method of choice, especially for finer wines. A certain savoir faire is often associated with the opening of a bottle of wine, and a variety of uncorking devices have been developed to assist in the presentation. The uncorking task is complicated by the nature of the cork material. While cork is elastically compressible, it is also somewhat friable, and is subject to crumbling when dry or exposed to excessive force. Being a natural product there is also an inherent degree of nonhomogeneity. The cumulative effect of these factors has resulted in a plethora of uncorking devices. Most of the more recent inventions use a worm-like helical "shaftless" corkscrew to minimize the over-all expansion of the cork when the corkscrew is inserted. Expansion is undesirable as it increases the radial force on the perimeter of the cork against the interior wall of the neck of the bottle, making the cork harder to extract. The older type of corkscrew is the auger "shaft" type corkscrews. The inserted "shaft" tends to expand the cork outwards, making uncorking more difficult. Rydgren U.S. Pat. No. 5,031,486 discusses this effect. Note, that both types of corkscrews have a very low thread count with a high degree of pitch and a wide flight so as to distribute the twisting action through out the cork, therein reducing the probability of the cork crumbling. Other, uncorking devices have been described in the literature, such as needles through which a gas is pumped into the bottle, but in general these techniques have not enjoyed the commercial success of the corkscrew.
Mechanized corkscrews, and in particular electric corkscrews, have been described in the prior art, as a means of automating the uncorking process. Manual uncorking using a corkscrew is not particularly physically rigorous, however it does require a repetitious twisting action, which can become difficult after several bottles. The twisting action can be extremely painful for someone with arthritis, or carpal tunnel syndrome. Mechanized corkscrews alleviate the twisting action, and all but eliminate the physical effort, however, generally, with coincident deleterious effects on the cork. For instance, Spencer U.S. Pat. No. 5,079,975 discloses an automatic corkscrew, wherein the force of the rotating corkscrew extracts the cork into the "extraction tube" . During the extraction, the corkscrew penetrates through the base of the cork, which can result in cork grinds being conveyed into the bottle. Secondly, the torque required to extract the cork is on the order of 2-3 times the torque required to twist the corkscrew into the cork, reaching a peak torque just prior to the cork yielding to the extraction forces. Twisting the corkscrew into the cork requires only approximately 1 Newton-meter, however to pull the cork out using a corkscrew with a 45 degree pitch (1.4 mechanical advantage) varies depending on the percent of compression and nature of the cork, but is generally on the order of 2.5-3.5 Newton-meters. This level of torque would create a pulling force of 26 to 38 Kg on the cork. This is sufficient force to cause considerable grinding action on the cork by the rotating corkscrew, hence the coincident deleterious effects on the cork.
Another consideration, particularly for battery powered corkscrews as disclosed in Spencer U.S. Pat. No. 5,079,975, is that the readily available commercial drivers have only a finite amount of dynamic torque. The dynamic torque, while being more than adequate for twisting in the corkscrew, is, without gear reduction modification or a much more expensive driver, marginal at the peak torque demand during the cork extraction. The problem of marginal torque is further exacerbated wherein it is desirous to extract the cork without previously removing the packaging seal. It should be noted that in serving large parties of people, where one is most likely to employ an electric corkscrew, the packaging seal is frequently not removed, because it takes as much time to take it off as it does to uncork the bottle.
Accordingly, a statement of the problem is the need for a mechanized corkscrew which mimics the action of a manual corkscrew, wherein the bottom of the cork is not pierced during the uncorking. Like a manual corkscrew, the mechanized corkscrew has to be portable, being easily taken to a table, and preferably cordless. It should rapidly de-cork(discharge the cork), and be ready for reuse. Twisting movement should be kept to a minimum. A further desirable feature is the ability to partially extract the cork, such that at a later time the cork can be removed from the bottle by hand just prior to pouring.
A narrower statement of the problem is the need for a mechanized corkscrew which can mimic the action of a winged manual corkscrew. The winged manual corkscrew has a sliding element that consists of a bell shaped flange and a geared cam, lever arm assembly. The bell shaped flange aligns the corkscrew centrally over the cork. The corkscrew is distally mounted on a notched shaft which moves on a bearing coaxially within the sliding element, wherein movement of the corkscrew relative to the sliding element rotates a pair of cam shaped gears on the sliding element which are engaged with the notched shaft. Each of the cam shaped gears has a lever arm (wing), and the wings pivot upward as the corkscrew moves downward. To uncork a bottle using the winged manual corkscrew, the same is positioned atop the bottle. The bell shaped flange settles flush and collinearly with the mouth of the bottle, therein aligning the concentric corkscrew, which is recessed within a bore of the sliding element, with the center of the cork. The corkscrew is twisted into the cork, and as it penetrates the cork, moving downward relative to the sliding element, the wings are raised. When the corkscrew has been twisted into the cork approximately 35 mm, the wings have been raised from a vertical to a horizontal position. The cork is extracted by applying equal and downward force on the opposing wings, which cause the corkscrew to move upward relative to the sliding element. The cork, which is embedded with the corkscrew, is pulled out of the bottle into the bell shaped flange and the bore of the sliding element. The winged manual corkscrew is de-corked by counter-rotating the corkscrew while holding the cork.
There are several features that bear some emphasis, when examining the action of the winged manual corkscrew, which in operation is similar to almost all manual corkscrews. The first feature is that the corkscrew is not used as an auger for conveying the cork out of the bottle, but simply as a means of attaching the cork to a lever arm, in this case a pair of lever arms. The consistency of cork is such that it is likely to crumble if augered, and some of the grinds will end up in the bottle. Secondly, the force required to pull the cork out of the bottle can be significant, and is variable from bottle to bottle, as a consequence of the natural variability of cork. Thirdly, during the extraction, there is no twisting, as this would make it difficult to keep the bottle from spinning while simultaneously manning the corkscrew.
Therein, the instant invention is a mechanized corkscrew which mimics the action of a winged manual corkscrew, that consists of a corkscrew apparatus and a mechanical power source, wherein the mechanical power source is preferably a cordless electric reversible motor powered by interchangeable, rechargeable batteries. The instant invention is designed to uncork a wine bottle in 3 or 4 seconds, and can be de-corked and reset in a matter of just a few seconds.